U.S. patent number 8,864,760 [Application Number 13/793,632] was granted by the patent office on 2014-10-21 for methods and systems for use in controlling tissue ablation volume by temperature monitoring.
This patent grant is currently assigned to Dfine, Inc.. The grantee listed for this patent is Dfine, Inc.. Invention is credited to Aaron Germain, Kirti P. Kamdar, Andrew Kohm, Steve Kramer, Robert Poser.
United States Patent |
8,864,760 |
Kramer , et al. |
October 21, 2014 |
Methods and systems for use in controlling tissue ablation volume
by temperature monitoring
Abstract
This invention relates to medical methods, instruments and
systems for creating a controlled lesion using temperature to
control the growth of the lesion. The treatment can be used in any
tissue area and is particularly useful in or around a vertebral
body. The features relating to the methods and devices described
herein can be applied in any region of soft or hard tissue
including bone or hard tissue.
Inventors: |
Kramer; Steve (Mountain View,
CA), Kamdar; Kirti P. (Los Gatos, CA), Kohm; Andrew
(Foster City, CA), Poser; Robert (Scotts Valley, CA),
Germain; Aaron (Campbell, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Dfine, Inc. |
San Jose |
CA |
US |
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Assignee: |
Dfine, Inc. (San Jose,
CA)
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Family
ID: |
49235993 |
Appl.
No.: |
13/793,632 |
Filed: |
March 11, 2013 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20130261615 A1 |
Oct 3, 2013 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13755548 |
Jan 31, 2013 |
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PCT/US2013/024019 |
Jan 31, 2013 |
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61616359 |
Mar 27, 2012 |
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61659604 |
Jun 14, 2012 |
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Current U.S.
Class: |
606/41; 606/38;
606/34 |
Current CPC
Class: |
A61B
18/1206 (20130101); A61B 18/148 (20130101); A61B
18/08 (20130101); A61B 18/1492 (20130101); A61B
18/12 (20130101); A61B 18/1477 (20130101); A61B
2018/00339 (20130101); A61B 17/1671 (20130101); A61B
18/20 (20130101); A61B 2018/00577 (20130101); A61B
2018/126 (20130101); A61B 2018/1253 (20130101); A61B
18/1815 (20130101); A61B 2018/00702 (20130101); A61B
2218/007 (20130101); A61B 2018/00642 (20130101); A61B
2018/00791 (20130101); A61B 2018/00678 (20130101); A61B
2018/00684 (20130101); A61B 2018/00797 (20130101); A61B
17/1642 (20130101); A61B 2218/002 (20130101) |
Current International
Class: |
A61B
18/12 (20060101) |
Field of
Search: |
;606/34,38,41 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2004-242936 |
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Sep 2004 |
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JP |
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WO 93/04634 |
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Mar 1993 |
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WO |
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WO 2003/101308 |
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Dec 2003 |
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WO |
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WO 2008/076330 |
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Jun 2008 |
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WO |
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WO 2008/084479 |
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Jul 2008 |
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WO |
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WO 2010/039894 |
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Apr 2010 |
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WO |
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WO 2011/137357 |
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Nov 2011 |
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WO |
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WO 2011/137377 |
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Nov 2011 |
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WO |
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WO 2013/147990 |
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Oct 2013 |
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WO |
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Primary Examiner: Della; Jaymi
Attorney, Agent or Firm: Levine Bagade Han LLP
Parent Case Text
RELATED APPLICATION DATA
This application is a continuation of U.S. patent application Ser.
No. 13/755,548 filed Jan. 31, 2013 and a continuation of
International Patent Application No PCT/US2013/024019 filed Jan.
31, 2013, both of which are non-provisionals of U.S. Provisional
Patent Application No. 61/616,359 filed Mar. 27, 2012 and U.S.
Provisional Patent Application No. 61/659,604 filed Jun. 14, 2012,
the contents of each of which are incorporated herein by reference
in their entirety.
Claims
The invention claimed is:
1. A medical device for creating a region of heated tissue using
temperature to monitor a desired profile of the region, the medical
device, comprising: a shaft coupled to a handle, where the handle
includes a connector for electrically coupling to a source of
energy; a first temperature detecting element spaced axially and
proximally along the shaft from a proximal end of an energy
transfer portion located at a working end of the shaft; a second
temperature detecting element spaced proximally from the first
temperature detecting element; where the first and second
temperature detecting elements are configured to independently and
respectively provide a first and a second actual temperature
measurement; and an energy controller capable of delivering energy
from the source of energy to the energy transfer portion, the
energy controller configured to control the delivering of the
energy in response to comparing at least the first or second actual
temperature measurements to at least one associated temperature,
where the associated temperature correlates to a previously
measured region of heated tissue having a known profile.
2. The medical device of claim 1, where the shaft includes an
articulating portion where the energy transfer portion is located
distally to the articulating portion.
3. The medical device of claim 1, the shaft and the handle are
configured to receive an impact force applied on the handle and
transfer the impact force to a distal end of the shaft.
4. The medical device of claim 1, where the energy transfer unit
comprises an extendable element and a portion of the shaft, where
the extendable element is configured to extend axially relative to
a distal end of the shaft.
5. The medical device of claim 1, where at least one of the first
and second temperature detecting elements is axially moveable along
the shaft independently of the energy transfer portion.
6. The medical device of claim 1, further comprising an introducer
cannula having a length, where the shaft further includes a first
and a second visual marker on a proximal end of the shaft adjacent
to the handle, where each first and second visual marker
corresponds to the first or second temperature detecting element,
such that when placed within the introducer cannula, the first and
second visual marker allow determination of whether the first or
second temperature detecting element is distally adjacent to an end
of the introducer cannula.
7. The medical device of claim 1, where the shaft further comprises
a first sleeve located concentrically within a second sleeve, the
shaft having a distal portion comprising the working end capable of
moving reversibly between a linear configuration and an articulated
configuration in response to movement of an actuating portion
coupled to the handle, where the articulated configuration is
limited to a single plane, and where the first and second sleeves
comprise a series of slots or notches to limit deflection of the
working end to the articulated configuration, where the series of
slots or notches are radially offset between the first sleeve and
second sleeve; and where the actuating portion includes a ratchet
mechanism to permit temporary locking of the working end in a
certain degree of rotation.
8. The medical device of claim 7, further comprising a
force-limiting assembly coupled between the actuating portion and
the first sleeve such that upon reaching a threshold force, the
actuating portion disengages the first sleeve.
9. The medical device of claim 7 further comprising, a sharp tip
located at a distal tip of the working end of the shaft, the sharp
tip adapted to penetrate hard tissue and a point of the sharp tip
is offset to engage hard tissue when advanced therein to assist in
deflecting the working end.
10. The medical device of claim 7, wherein the first sleeve is
coupled to the actuating portion coupled to the handle such that
rotation of the actuating portion coupled to the handle is
configured to cause axial movement of the first sleeve to deform
the working end into the articulated configuration.
Description
FIELD OF THE INVENTION
This invention relates to medical methods, instruments and systems
for creating a controlled lesion using temperature to control the
growth of the lesion. The treatment can be used in any tissue area
and is particularly useful in or around a vertebral body. The
features relating to the methods and devices described herein can
be applied in any region of soft or hard tissue including bone or
hard tissue.
SUMMARY OF THE INVENTION
Methods and devices described herein relate to improved treatment
of tissue using temperature information to assist in producing a
desired region of treated tissue and/or using temperature
information to produce a region of treated tissue of a known or
pre-determined sized.
In one variation, the methods described herein include of applying
energy to tissue by positioning a treatment device into a tissue
area, the treatment device having an energy transfer portion
located at a distal portion of a shaft, the treatment device
further including at least a first temperature detecting element
coupled to the shaft and axially along the shaft from the energy
transfer portion; applying energy to the energy transfer portion to
produce a region of heated tissue about the energy transfer
portion; continuing application of energy to expand the region of
heated tissue; measuring an actual temperature of a tissue area
adjacent to the first temperature detecting element; and monitoring
a size of the region of heated tissue as it expands by comparing
the temperature to at least one associated temperature, such that
the associated temperature correlates to a previously measured
region of heated tissue having a known size.
The method can include controlling expansion of the region of
heated tissue after comparing the temperature to at least one
associated temperature. Optionally controlling expansion of the
region of heated tissue comprises ceasing application of energy
when the temperature reaches the associated temperature.
The areas of tissue that can be treated by the methods and devices
described herein include hard and soft tissue. The methods are
particularly useful for treatment of a vertebral body and/or a
rumor within the vertebral body. However, the method and devices
can be applied to any number of body tissues.
In one variation of the methods described herein monitoring the
size of the area of heated tissue further comprises determining a
characteristic selected from a volume of the region of heated
tissue and a length of the region of heated tissue. Monitoring the
size of the region of heated tissue can also comprise providing
user feedback selected from the group consisting of: the
temperature is approaching the associated temperature, the
approximated length of the heated tissue.
The methods can also include monitoring the size of the region of
heated tissue by adjusting a power supplied to the energy transfer
portions during the continuing application of energy to control the
growth of the region of heated tissue.
In certain variations, an axial distance between the first
temperature detecting element and the energy transfer portion can
be adjusted between a plurality of positions, the method further
comprising selecting one of the positions to adjust the axial
distance between the temperature detecting element and the energy
transfer portion.
The associated temperature can comprise a plurality of associated
temperatures each corresponding to a plurality of previously
measured regions of heated tissue, where each of the plurality of
previously measured regions of heated tissue comprises a distinct
shape. In such cases the method can further comprise controlling
expansion of the region of heated tissue after comparing the
temperature to the at least one associated temperature by selecting
one of the plurality of associated temperatures and ceasing
application of energy when the temperature reaches the selected
associated temperature.
In an additional variation, the present disclosure includes a
method of using temperature measurements to produce a region of
heated tissue in the vertebral body. For example, such a method can
comprise inserting a treatment device into a tissue area, the
treatment device having an energy transfer portion located at a
distal portion of a shaft, the treatment device further including
at least one temperature detecting element coupled to the shaft;
selecting an actual location in tissue that corresponds to a
perimeter of a desired treatment zone haying a desired profile;
positioning the temperature detecting element at or near the actual
location; applying energy to the energy transfer portion to produce
the region of heated tissue about the energy transfer portion;
continuing application of energy to cause growth of the region of
heated tissue; measuring a temperature of a tissue area located
adjacent to the temperature detecting element; and comparing the
temperature to an associated temperature to control the application
of energy to the energy transfer unit, where the associated
temperature correlates to a previously determined region of heated
tissue having a known profile where the known profile is similar to
the desired profile.
Variations of the method can include at least a first temperature
detecting element and a second temperature detecting element, where
the second temperature detecting element is located proximally to
the first temperature detecting element; where measuring the
temperature comprises measuring a first temperature and a second
temperature at the respective temperature detecting elements; and
where comparing the temperature to the associated temperature to
control the application of energy to the energy transfer unit
comprises selecting either the first or second temperatures to the
associated temperature.
The present disclosure also includes medical systems for creating
regions of heated tissue using temperature to monitor a desired
profile of the regions. For example, the medical system can
include: an energy controller capable of controlling energy
delivery in response to comparing at least one temperature
measurements to at least at least one associated temperature, where
the associated temperature correlates to a previously measured
region of heated tissue having a known profile; a treatment device
having a shaft coupled to a handle, where the handle includes a
connector for electrically coupling to the energy control unit; a
shaft extending from the handle to a distal portion, an energy
transfer portion for delivering energy from the power supply to
tissue located at the distal portion; at least a first and second
temperature detecting elements spaced proximally from a proximal
end of the energy transfer portion, each temperature sensor
configured to independently and respectively provide it first and a
second actual temperature measurements to the energy
controller.
In one variation, the medical system comprises an extendable
element and a portion of the shaft, where the extendable element is
configured to extend axially relative to a distal end of the shaft.
In an additional variation, at least one of the temperature
detecting elements is axially moveable along the shaft
independently of the energy transfer unit.
The present disclosure also includes medical devices for creating
regions of heated tissue using temperature to monitor a desired
profile of the regions. Such a medical device can include a shaft
coupled to a handle, where the handle includes a connector for
electrically coupling to a source of energy; a first temperature
detecting element spaced axially proximally along the shaft from a
proximal end of the energy transfer portion; a second temperature
detecting element spaced proximally from the first temperature
detecting element; where the first and second temperature detecting
elements are configured to independently and respectively provide a
first and a second actual temperature measurements.
The device can further include 34 an energy controller capable of
delivering the source of energy to the energy transfer portion, the
energy controller configured to control energy delivery in response
to comparing at least the first or second actual temperature
measurements to at least at least one associated temperature, where
the associated temperature correlates to a previously measured
region of heated tissue having a known profile.
Another variation of the method includes a method of treating a
tumor in or near bone. For example, such a method can include
providing an elongated shaft with an articulating working end
carrying first and second polarity electrodes; utilizing
articulation of the working end to navigate the working end to a
position in or near a bone tumor; activating an RF source, such
that when activated, current flows between the first and second
polarity electrodes to ablate the tumor; and terminating activation
of the RF source when a temperature sensor spaced apart from the
second polarity electrode reaches a predetermined temperature.
In one variation, the temperature sensor spacing from the second
polarity electrode is configured to provide a predetermined tissue
ablation volume. In an alternate variation, the shaft has a
plurality of temperature sensors spaced apart from the second
polarity electrode to provide a plurality of predetermined tissue
ablation volumes.
Variations of the device can include one or more lumens that extend
through the shaft and working end. These lumens can exit at a
distal tip of the device or through a side opening in a wall of the
device. The lumen can include a surface comprising a lubricious
polymeric material. For example, the material can comprise any
bio-compatible material having low frictional properties (e.g.,
TEFLON.RTM., a polytetrafluroethylene (PTFE), FEP (Fluorinated
ethylenepropylene), polyethylene, polyamide, ECTFE
(Ethylenechlorotrifluoro-ethylene), ETFE, PVDF, polyvinyl chloride
and silicone).
Variations of the access device and procedures described above
include combinations of features of the various embodiments or
combination of the embodiments themselves wherever possible.
The methods, devices and systems described herein can be combined
with the following commonly assigned patent applications and
provisional applications, the entirety of each of which is
incorporated by reference herein: application Ser. No. 12/571,174
filed Sep. 30, 2009; application Ser. No. 12/578,455 filed Oct. 13,
2009; application Ser. No. 13/083,411 filed Apr. 8, 2011;
application Ser. No. 13/097,998 filed Apr. 29, 2011; application
Ser. No. 13/098,116 filed Apr. 29, 2011; application Ser. No.
13/302,927 filed Nov. 22, 2011; Provisional Application No.
61/194,766 filed Sep. 30, 2008; Provisional Application No.
61/104,380 filed Oct. 10, 2008; Provisional Application No.
61/322,281 filed Apr. 8, 2010; Provisional Application No.
61/329,220 filed Apr. 29, 2010; Provisional Application No.
61/329,394 filed Apr. 29, 2010; Provisional Application No.
61/416,042 filed Nov. 22, 2010; Provisional Application No.
61/616,359 filed Mar. 27, 2012; and Provisional Application No.
61/659,604.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a plan view of an osteotome of the invention.
FIG. 2 is a side view of the osteotome of FIG. 1.
FIG. 3 is a cross sectional view of the osteotome of FIG. 1.
FIG. 4 is an enlarged sectional view of the handle of the osteotome
of FIG. 1.
FIG. 5 is an enlarged sectional view of the working end of the
osteotome of FIG. 1.
FIG. 6A is a sectional view of the working end of FIG. 5 in a
linear configuration.
FIG. 6B is a sectional view of the working end of FIG. 5 in a
curved configuration.
FIGS. 7A-7C are schematic sectional views of a method of use of the
osteotome of FIG. 1.
FIG. 8 is another embodiment of an osteotome working end.
FIG. 9 is another embodiment of an osteotome working end.
FIG. 10 is another variation of an osteotome with an outer
sleeve.
FIG. 11 is a cut-away view of the working end of the osteotome of
FIG. 10.
FIG. 12A is sectional view of another embodiment of working end,
taken along line 12A-12A of FIG. 11.
FIGS. 12B and 12C illustrate additional variations of preventing
rotation between adjacent sleeves.
FIG. 13 is sectional view of another working end embodiment similar
to that of FIG. 11.
FIG. 14 is a cut-away perspective view of the working end of FIG.
13.
FIG. 15 illustrates a variation of an osteotome as described herein
having electrodes on a tip of the device and another electrode on
the shaft.
FIG. 16 illustrates an osteotome device as shown in FIG. 15 after
being advanced into the body and where current passes between
electrodes.
FIG. 17 illustrates a variation of a device as described herein
further including a connector for providing energy at the working
end of the device.
FIGS. 18A and 18B illustrate a device having a sharp tip as
disclosed herein where the sharp tip is advanceable from the distal
end of the shaft.
FIG. 19 shows a cross sectional view of the device illustrated in
FIG. 18B and also illustrates temperature sensing elements located
on device.
FIG. 20 shows a variation of a device where the inner sleeve is
extended from the device and where current is applied between the
extended portion of the inner sleeve and the shaft to treat
tissue.
FIG. 21 illustrates a variation of a device as described herein
further including an extendable helical electrode carried by the
working end of the device.
FIGS. 22A and 22B illustrate the device of FIG. 21 with the helical
electrode in a non-extended position and an extended position.
FIGS. 22C and 22D illustrate charts of variations of electrodes
having ablated volumes given a particular duration of an ablation
cycle.
FIG. 23 illustrates the working end of the device of FIG. 21 in a
vertebral body with the helical electrode delivering Rf energy to
ablate tissue.
FIG. 24 illustrates the working end of an osteotome similar to that
of FIGS. 22A-22B showing temperature sensors disposed within the
working end.
FIG. 25 illustrates another osteotome working end similar to that
of FIG. 25.
FIGS. 26A to 26E depict variations of devices having multiple
temperature sensing elements adjacent to energy transfer
portions.
FIGS. 27A to 27C illustrates the use of one or more temperature
sensing elements to monitor and/or control the growth of a region
of treated tissue.
DETAILED DESCRIPTION
Referring to FIGS. 1-5, an apparatus or osteotome 100 is shown that
is configured for accessing the interior of a vertebral body and
for creating a pathway in vertebral cancellous bone to receive hone
cement. In one embodiment, the apparatus is configured with an
extension portion or member 105 for introducing through a pedicle
and wherein a working end 110 of the extension member can be
progressively actuated to curve a selected degree and/or rotated to
create a curved pathway and cavity in the direction of the midline
of the vertebral body. The apparatus can be withdrawn and bone fill
material can be introduced through a bone cement injection cannula.
Alternatively, the apparatus 100 itself can be used as a cement
injector with the subsequent injection of cement through a lumen
112 of the apparatus.
In one embodiment, the apparatus 100 comprises a handle 115 that is
coupled to a proximal end of the extension member 105. The
extension member 105 comprises an assembly of first (outer) sleeve
120 and a second (inner) sleeve 122, with the first sleeve 120
having a proximal end 124 and distal end 126. The second sleeve 122
has a proximal end 134 and distal end 136. The extension member 105
is coupled to the handle 115, as will be described below, to allow
a physician to drive the extension member 105 into bone while
contemporaneously actuating the working end 110 into an actuated or
curved configuration (see FIG. 6). The handle 115 can be fabricated
of a polymer, metal or any other material suitable to withstand
hammering or impact forces used to drive the assembly into bone
(e.g., via use of a hammer or similar device on the handle 115).
The inner and outer sleeves are fabricated of a suitable metal
alloy, such as Stainless steel or NiTi. The wall thicknesses of the
inner and outer sleeves can range from about 0.005'' to 0.010''
with the outer diameter the outer sleeve ranging from about 2.5 mm
to 5.0 mm.
Referring to FIGS. 1, 3 and 4, the handle 115 comprises both a
first grip portion 140 and a second actuator portion indicated at
142. The grip portion 140 is coupled to the first sleeve 120 as
will be described below. The actuator portion 142 is operatively
coupled to the second sleeve 122 as will be described below. The
actuator portion 142 is rotatable relative to the grip portion 140
and one or more plastic flex tabs 145 of the grip portion 140 are
configured to engage notches 146 in the rotatable actuator portion
142 to provide tactile indication and temporary locking of the
handle portions 140 and 142 in a certain degree of rotation. The
flex tabs 145 thus engage and disengage with the notches 146 to
permit ratcheting (rotation and locking) of the handle portions and
the respective sleeve coupled thereto.
The notches or slots in any of the sleeves can comprise a uniform
width along the length of the working end or can comprise a varying
width. Alternatively, the width can be selected in certain areas to
effectuate a particular curved profile. In other variation, the
width can increase or decrease along the working end to create a
curve having a varying radius. Clearly, it is understood that any
number of variations are within the scope of this disclosure.
FIG. 4 is a sectional view of the handle showing a mechanism for
actuating the second inner sleeve 122 relative to the first outer
sleeve 120. The actuator portion 142 of the handle 115 is
configured with a fast-lead helical groove indicated at 150 that
cooperates with a protruding thread 149 of the grip portion 140 of
the handle. Thus, it can be understood that rotation of the
actuation portion 142 will move this portion to the position
indicated at 150 (phantom view). In one embodiment, when the
actuator portion 142 is rotated a selected amount from about
45.degree. to 720.degree., or from about 90.degree. to 360.degree.,
the inner sleeve 122 is lifted proximally relative to the grip
portion 140 and outer sleeve 120 to actuate the working end 110. As
can be seen in FIG. 4 the actuator portion 142 engages flange 152
that is welded to the proximal end 132 of inner sleeve 122. The
flange 152 is lifted by means of a ball bearing assembly 154
disposed between the flange 152 and metal bearing surface 155
inserted into the grip portion 140 of the handle. Thus, the
rotation of actuator 142 can lift the inner sleeve 122 without
creating torque on the inner sleeve.
Now turning to FIGS. 5, 6A and 6B, it can be seen that the working
end 110 of the extension member 105 is articulated by cooperating
slotted portions of the distal portions of outer sleeve 120 and
inner sleeve 122 that are both thus capable of bending in a
substantially tight radius. The outer sleeve 120 has a plurality of
slots or notches 162 therein that can be any slots that are
perpendicular of angled relative to the axis of the sleeve. The
inner sleeve 122 has a plurality of slots or notches indicated at
164 that can be on an opposite side of the assembly relative to the
slots 162 in the outer sleeve 120. The outer and inner sleeves are
welded together at the distal region indicated at weld 160. It thus
can be understood that when inner sleeve 122 is translated in the
proximal direction, the outer sleeve will be flexed as depicted in
FIG. 613. It can be understood that by rotating the actuator handle
portion 142 a selected amount, the working end can be articulated
to a selected degree.
FIGS. 4, 5, 6A and 6B further illustrate another element of the
apparatus that comprises a flexible flat wire member 170 with a
proximal end 171 and flange 172 that is engages the proximal side
of flange 152 of the inner sleeve 122. At least the distal portion
of the flat wire member 170 is welded to the inner sleeve at weld
160. This flat wire member thus provides a safety feature to retain
the working end in the event that the inner sleeve fails at one of
the slots 164
Another safety feature of the apparatus comprises a torque limiter
and release system that allows the entire handle assembly 115 to
freely rotate--for example if the working end 110 is articulated,
as in FIG. 6B, when the physician rotates the handle and when the
working end is engaged in strong cancellous bone. Referring to FIG.
4, the grip portion 142 of the handle 115 engages a collar 180 that
is fixed to a proximal end 124 of the outer sleeve 120. The collar
180 further comprises notches 185 that are radially spaced about
the collar and are engaged by a ball member 186 that is pushed by a
spring 188 into notches 185. At a selected force, for example a
torque ranging from greater than about 0.5 inch*lbs but less that
about 7.5 inch*lbs, 5.0 inch*lbs or 2.5 inch*lbs, the rotation of
the handle 115 overcomes the predetermined limit. When the torque
limiter assembly is in its locked position, the ball bearing 186 is
forced into one of the notches 185 in the collar 180. When too much
torque is provided to the handle and outer sleeve, the ball bearing
186 disengages the notch 185 allowing the collar 180 to turn, and
then reengages at the next notch, releasing anywhere from 0.5
inch*lbs to 7.5 inch*lbs of torque.
Referring to FIGS. 6A and 6B, it can be understood that the inner
sleeve 122 is weakened on one side at its distal portion so as to
permit the inner sleeve 122 to bend in either direction but is
limited by the location of the notches in the outer sleeve 120. The
curvature of any articulated configuration is controlled by the
spacing of the notches as well as the distance between each notch
peak. The inner sleeve 122 also has a beveled tip for entry through
the cortical bone of a vertebral body. Either the inner sleeve or
outer sleeve can form the distal tip.
Referring to FIGS. 7A-7C, in one variation of use of the device, a
physician taps or otherwise drives a stylet 200 and introducer
sleeve 205 into a vertebral body 206 typically until the stylet tip
208 is within the anterior 1/3 of the vertebral body toward
cortical bone 210 (FIG. 7A). Thereafter, the stylet 200 is removed
and the sleeve 205 is moved proximally (FIG. 7B). As can be seen in
FIG. 7B, the tool or osteotome 100 is inserted through the
introducer sleeve 205 and articulated in a series of steps as
described above. The working end 110 can be articulated
intermittently while applying driving forces and optionally
rotational forces to the handle 115 to advance the working end
through the cancellous bone 212 to create path or cavity 215. The
tool is then tapped to further drive the working end 110 to, toward
or past the midline of the vertebra. The physician can
alternatively articulate the working end 110, and drive and rotate
the working end further until imaging shows that the working end
100 has created a cavity 215 of an optimal configuration.
Thereafter, as depicted in FIG. 7C, the physician reverses the
sequence and progressively straightens the working end 110 as the
extension member is withdrawn from the vertebral body 206.
Thereafter, the physician can insert a bone cement injector 220
into the path or cavity 215 created by osteotome 100. FIG. 7C
illustrates a bone cement 222, for example a PMMA cement, being
injected from a bone cement source 225.
In another embodiment (not shown), the apparatus 100 can have a
handle 115 with a Luer fitting for coupling a bone cement syringe
and the bone cement can be injected through the lumen 112 of the
apparatus. In such an embodiment FIG. 9, the lumen can have a
lubricious surface layer or polymeric lining 250 to insure least
resistance to bone cement as it flows through the lumen. In one
embodiment, the surface or lining 250 can be a fluorinated polymer
such as TEFLON.RTM. or polytetrafluroethylene (PTFE). Other
suitable fluoropolymer resins can be used such as FEP and PFA.
Other materials also can be used such as FEP (Fluorinated
ethylenepropylene), ECTFE (Ethylenechlorotrifluoro-ethylene), ETFE,
Polyethylene, Polyamide, PVDF, Polyvinyl chloride and silicone. The
scope of the invention can include providing a polymeric material
having a static coefficient of friction of less than 0.5, less than
0.2 or less than 0.1.
FIG. 9 also shows the extension member or shaft 105 can be
configured with an exterior flexible sleeve indicated at 255. The
flexible sleeve can be any commonly known biocompatible material,
for example, the sleeve can comprise any of the materials described
in the preceding paragraph.
As also can be seen in FIG. 9, in one variation of the device 100,
the working end 110 can be configured to deflect over a length
indicated at 260 in a substantially smooth curve. The degree of
articulation of the working end 100 can be at least 45.degree.,
90.degree., 135.degree. or at least 180.degree. as indicated at 265
(FIG. 9). In additional variations, the slots of the outer 120 and
inner sleeves 120 can be varied to produce a device having a radius
of curvature that varies among the length 260 of the device
100.
In another embodiment of the invention, the inner sleeve can be
spring loaded relative the outer sleeve, in such a way as to allow
the working end to straighten under a selected level of force when
pulled in a linear direction. This feature allows the physician to
withdraw the assembly from the vertebral body partly or completely
without further rotation the actuating portion 142 of handle 115.
In some variations, the force-limiter can be provided to allow less
than about 10 inch*lbs of force to be applied to bone.
In another embodiment shown in FIG. 8, the working end 110 is
configured with a tip 240 that deflects to the position indicated
at 240' when driven into bone. The tip 240 is coupled to the sleeve
assembly by resilient member 242, for example a flexible metal such
as stainless steel or NiTi. It has been found that the flexing of
the tip 240 causes its distal surface area to engage cancellous
hone which can assist in deflecting the working end 110 as it is
hammered into bone.
In another embodiment of the invention (not shown), the actuator
handle can include a secondary or optional) mechanism for actuating
the working end. The mechanism would include a hammer-able member
with a ratchet such that each tap of the hammer would advance
assembly and progressively actuate the working end into a curved
configuration. A ratchet mechanism as known in the art would
maintain the assembly in each of a plurality of articulated
configurations. A release would be provided to allow for release of
the ratchet to provide for straightening the extension member 105
for withdrawal from the vertebral body.
FIGS. 10 and 11 illustrate another variation of a bone treatment
device 400 with a handle 402 and extension member 405 extending to
working end 410 having a similar construction to that FIGS. 1 to
6B. The device 400 operates as described previously with notched
first (outer) sleeve 120 and cooperating notched second (inner)
sleeve 122. However, the variation shown in FIGS. 10 and 11 also
includes a third concentric notched sleeve 420, exterior to the
first 120 and second 122 sleeves. The notches or slots in sleeve
420 at the working end 410 permit deflection of the sleeve as
indicated at 265 in FIG. 11.
FIG. 10 also illustrates the treatment device 400 as including a
luer fitting 412 that allows the device 402 to be coupled to a
source of a filler material (e.g., a bone filler or bone cement
material). The luer can be removable from the handle 402 to allow
application of an impact force on the handle as described above.
Moreover, the bier fitting 402 can be located on the actuating
portion of the handle, the stationary part of the handle or even
along the sleeve. In any case, variations of the device 400 permit
coupling the filler material with a lumen extending through the
sleeves (or between adjacent sleeves) to deposit filler material at
the working end 410. As shown by arrows 416, filler material can be
deposited through a distal end of the sleeves (where the sharp tip
is solid) or can be deposited through openings in a side-wall of
the sleeves. Clearly, variations of this configuration are within
the scope of those familiar in the field.
In some variations, the third notched sleeve 420 is configured with
its smooth (non-notched) surface 424 disposed to face inwardly on
the articulated working end (FIG. 11) such that a solid surface
forms the interior of the curved portion of the working end 410.
The smooth surface 424 allows withdrawal of the device 110 into a
cannula or introducer 205 without creating a risk that the slots or
notches become caught on a cannula 205 (see e.g., FIG. 7B).
As shown in FIGS. 10-11, the third (outermost) sleeve 420 can
extend from an intermediate location on the extension member 405 to
a distal end of the working end 410. However, variations of the
device include the third sleeve 420 extending to the handle 402.
However, the third sleeve 420 is typically not coupled to the
handle 402 so that any rotational force or torque generated by the
handle 402 is not directly transmitted to the third sleeve 420.
In one variation, the third sleeve 420 is coupled to the second
sleeve 120 at only one axial location. In the illustrated example
shown in FIG. 11, the third sleeve 420 is affixed to second sleeve
420 by welds 428 at the distal end of the working end 410. However,
the welds or other attachment means (e.g., a pin, key/keyway,
protrusion, etc.) can be located on a medial part of the sleeve
420. The sleeve 420 can be fabricated of any bio-compatible
material. For example, in one variation, the third sleeve is
fabricated form a 3.00 mm diameter stainless steel material with a
wall thickness of 0.007''. The first, second and third sleeves are
sized to have dimensions to allow a sliding fit between the
sleeves.
FIG. 12A is a sectional view of extension member 405 of another
variation, similar to that shown in FIGS. 10-11. However, the
variation depicted by FIG. 12A comprises non-round configurations
of concentric slidable sleeves (double or triple sleeve devices).
This configuration limits or prevents rotation between the sleeves
and allows the physician to apply greater forces to the bone to
create a cavity. While FIG. 12A illustrates an oval configuration,
any non-round shape is within the scope of this disclosure. For
example, the cross-sectional shape can comprise a square,
polygonal, or other radially keyed configuration as shown in FIGS.
12B and 12C. As shown in FIG. 12C the sleeves can include a key 407
and a receiving keyway 409 to prevent rotation but allow relative
or axial sliding of the sleeves. The key can comprise any
protrusion or member that slides within a receiving keyway.
Furthermore, the key can comprise a pin or any raised protrusion on
an exterior or interior of a respective sleeve. In this
illustration, only the first 122 and second 120 sleeves are
illustrated. However, any of the sleeves can be configured with the
key/keyway. Preventing rotation between sleeves improves the
ability to apply force to bone at the articulated working end.
FIGS. 13-14 illustrate another variation of a working end 410 of an
osteotome device. In this variation, the working end 410 includes
one or more flat spring elements 450, 460a, 460b, 460c, 460d, that
prevent relative rotation of the sleeves of the assembly thus
allowing greater rotational forces to be applied to cancellous bone
from an articulated working end. The spring elements further urge
the working end assembly into a linear configuration. To articulate
the sleeves, a rotational force is applied to the handle as
described above, once this rotational force is removed, the spring
elements urge the working end into a linear configuration. As shown
in FIG. 13, one or more of the spring elements can extend through
the sleeves for affixing to a handle to prevent rotation.
Furthermore, the distal end 454 of flat spring element 450 is fixed
to sleeve assembly by weld 455. Thus, the spring element is fixed
at each end to prevent its rotation. Alternate variations include
one or more spring elements being affixed to the inner sleeve
assembly at a medial section of the sleeve.
As shown in FIGS. 13-14, variations of the osteotome can include
any number of spring elements 460a-460d. These additional spring
elements 460a-460d can be welded at either a proximal or distal end
thereof to an adjacent element or a sleeve to allow the element to
function as a leaf spring.
In an additional variation, the osteotome device can include one or
more electrodes 310, 312 as shown in FIG. 15. In this particular
example, the device 300 includes spaced apart electrodes having
opposite polarity to function in a bi-polar manner. However, the
device can include a monopolar configuration. Furthermore, one or
more electrodes can be coupled to individual channels of a power
supply so that the electrodes can be energized as needed. Any
variation of the device described above can be configured with one
or more electrodes as described herein.
FIG. 16 illustrates an osteotome device 300 after being advanced
into the body as discussed above. As shown by lines 315
representing current flow between electrodes, when required, the
physician can conduct RF current between electrodes 310 and 312 to
apply coagulative or ablative energy within the hone structure of
the vertebral body (or other hard tissue). While FIG. 16
illustrates RF current 315 flow between electrodes 310 and 312,
variations of the device can include a number of electrodes along
the device to apply the proper therapeutic energy. Furthermore, an
electrode can be spaced from the end of the osteotome rather than
being placed on the sharp tip as shown by electrode 310. In some
variations, the power supply is coupled to the inner sharp tip or
other working end of the first sleeve. In those variations with
only two sleeves, the second pole of the power supply is coupled
with the second sleeve (that is the exterior of the device) to form
a return electrode. However, in those variations having three
sleeves, the power supply can alternatively be coupled with the
third outer sleeve. In yet additional variations, the second and
third sleeves can both function as return electrodes. However, in
those devices that are monopolar, the return electrode will be
placed outside of the body on a large area of skin.
FIGS. 17 to 20 illustrate another variation of an articulating
probe or osteotome device 500. In this variation, the device 500
includes a working end 505 that carries one or more RF electrodes
that can be used to conduct current therethrough. Accordingly, the
device can be used to sense impedance of tissue, locate nerves, or
simply apply electrosurgical energy to tissue to coagulate or
ablate tissue. In one potential use, the device 500 can apply
ablative energy to a tumor or other tissue within the vertebra as
well as create a cavity.
FIGS. 17, 18A, 18B and 19, illustrate a variation of the device 500
as having a handle portion 506 coupled to a shaft assembly 510 that
extends along axis 512 to the articulating working end 505. The
articulating working end 505 can be actuatable as described above.
In addition, FIG. 17 shows that handle component 514a can be
rotated relative to handle component 514b to cause relative axial
movement between a first outer sleeve 520 and second inner sleeve
522 (FIG. 19) to cause the slotted working ends of the sleeve
assembly to articulate as described above. The working end 505 of
FIG. 19 shows two sleeves 520 and 522 that are actuatable to
articulate the working end, but it should be appreciated that a
third outer articulating sleeve can be added as depicted above. In
one variation, the articulating working end can articulate
90.degree. by rotating handle component 514a between 1/4 turn and
3/4 turn. The rotating handle component 514a can include defeats at
various rotational positions to allow for controlled hammering of
the working end into bone. For example, the detents can be located
at every 45.degree. rotation or can be located at any other
rotational increment.
FIG. 17 depict an RF generator 530A and RF controller 530B
connectable to an electrical connector 532 in the handle component
514a with a plug connector indicated at 536. The RF generator is of
the type known in the art for electrosurgical ablation. The outer
sleeve 520 comprises a first polarity electrode indicated at 540A
(+). However, any energy modality can be employed with the
device.
FIGS. 18A and 18B illustrate yet another variation of a working end
of a device for creating cavities in hard tissue. As shown, the
device 500 can include a central extendable sleeve 550 with a sharp
tip 552 that is axially extendable from passageway 554 of the
assembly of first and second sleeves 520 and 522 (FIG. 19). The
sleeve 550 can also include a second polarity electrode indicated
at 540B (-). Clearly, the first and second electrodes will be
electrically insulated from one another. In one variation, and as
shown in FIG. 19, the sleeve assembly can carry a thin sleeve 555
or coating of an insulative polymer such as PEEK or Ceramic to
electrically isolate the first polarity electrode 540A (+) from the
second polarity electrode 540B (-). The electrode can be deployed
by rotating knob 558 on the striking surface of handle component
514a (FIG. 17). The degree of extension of central sleeve 550 can
optionally be indicated by a slider tab 557 on the handle. In the
illustrated variation, the slider tab is located on either side of
handle component 514a (FIG. 17). Sleeve 550 can be configured to
extend distally beyond the assembly of sleeves 520 and 522 a
distance of about 5 to 15 mm.
Referring to FIG. 19, the central extendable sleeve 550 can have a
series of slots in at least a distal portion thereof to allow it to
bend in cooperation with the assembly of first and second sleeves
520 and 522. In the embodiment shown in FIG. 188, the central
sleeve 550 can optionally include a distal portion that does not
contain any slots. However, additional variations include slots on
the distal portion of the sleeve.
FIG. 19 further depicts an electrically insulative collar 560 that
extends length A to axially space apart the first polarity
electrode 540A (+) from the second polarity electrode 540B (-). The
axial length A can be from about 0.5 to 10 mm, and usually is from
1 to 5 mm. The collar can be a ceramic or temperature resistant
polymer.
FIG. 19 also depicts a polymer sleeve 565 that extends through the
lumen in the center of electrode sleeve 550. The polymer sleeve 565
can provide saline infusion or other fluids to the working end
and/or be used to aspirate from the working end when in use. The
distal portion of sleeve 550 can include one or more ports 566
therein for delivering fluid or aspirating from the site.
In all other respects, the osteotome system 500 can be driven into
bone and articulated as described above. The electrodes 540A and
540B are operatively coupled to a radiofrequency generator as is
known in the art for applying coagulative or ablative
electrosurgical energy to tissue. In FIG. 20, it can be seen that
RF current 575 is indicated in paths between electrodes 540A and
540B as shown by lines 575. RF generator 530A and controller 53011
for use with the devices described herein can include any number of
power settings to control the size of targeted coagulation or
ablation area. For example, the RF generator and controller can
have Low or power level 1 (5 watts), medium or power level 2 (10
Watts) and High or power level 3 (25 watts) power settings. The
controller 530B can have a control algorithm that monitors the
temperature of the electrodes and changes the power input in order
to maintain a constant temperature. At least one temperature
sensing element (e.g., a thermocouple) can be provided on various
portions of the device. For example, and as shown in FIG. 19, a
temperature sensing element 577 can be provided at the distal tip
of sleeve 550 tip while a second temperature sensing element 578
can be provided proximal from the distal tip to provide temperature
feedback to the operator to indicate the region of ablated tissue
during the application of RF energy. In one example, the second
temperature sensing element was located approximately 15 to 20 mm
from the distal tip.
FIG. 21 illustrates another variation of articulating osteotome 600
with RF ablation features. Variations of the illustrated osteotome
600 can be similar to the osteotome of FIGS. 17-188. In this
variation, the osteotome 600 of has a handle 602 coupled to shaft
assembly 610 as described above. The working end 610 again has an
extendable assembly indicated at 615 in FIG. 21 that can be
extended by rotation of handle portion 622 relative to handle 602.
The osteotome can be articulated as described previously by
rotating handle portion 620 relative to handle 602.
FIGS. 22A-22B are views of the working end 610 of FIG. 21 in a
first non-extended configuration (FIG. 22A) and a second extended
configuration (FIG. 228). As can be seen in FIGS. 22A-22B, the
extension portion 615 comprises an axial shaft 624 together with a
helical spring element 625 that is axially collapsible and
extendible. In one embodiment, the shaft can be a tube member with
ports 626 fluidly coupled a lumen 628 therein. In some variations,
the ports can carry a fluid to the working end or can aspirate
fluid from the working end.
In FIGS. 22A-22B, it can be seen that axial shaft 624, helical
spring element 625 together with sharp tip 630 comprise a first
polarity electrode (+) coupled to electrical source 530A and
controller 530B as described previously. An insulator 632 separates
the helical spring 625 electrode from the more proximal portion of
the sleeve which comprises opposing polarity electrode 640 (-). The
RF electrodes can function as described above (see FIG. 20) to
ablate tissue or otherwise deliver energy to tissue.
In one variation, the extension portion 615 can extend from a
collapsed spring length of 2 mm, 3 mm, 4 mm or 5 mm to an extended
spring length of 6 mm, 7 mm, 8 mm, 9 mm 10 mm or more. In the
working end embodiment 615 in FIG. 22B, the spring can comprise a
flat rectangular wire that assists in centering the spring 625
about shaft 624 and still can collapse to short overall length,
with the flat surfaces of rectangular wire oriented for stacking.
However, other variations are within the scope of the variations
described herein.
Of particular importance, it has been found that ability of the
osteotome 600 to ablate tissue is greatly enhanced over the
embodiment 500 of FIG. 20 by utilizing the helical spring. The use
of the spring 625 as an electrode provides significant improvements
in delivering energy. This spring provides (i) greatly increased
electrode surface area and (ii) a very greatly increased length of
relatively sharp edges provided by the rectangular wire--which
provides for edges from which RF current can jump. Because the
edges provide low surface area the concentration or density of RF
current is greater at the edges and allows for the RF current to
jump or arc. Both these aspects of the invention--increased
electrode surface area and increased electrode edge length--allow
for much more rapid tissue ablation.
In one aspect of the invention, the surface area of the spring
electrode 625 can be at least 40 mm.sup.2, at least 50 mm.sup.2, or
at least 60 mm.sup.2 over the spring electrode lengths described
above.
In another aspect of the invention, the total length of the 4 edges
of rectangular wire spring can be greater than 50 mm, greater than
100 mm or greater than 150 nun over the spring electrode lengths
described above.
In one example used in testing, an osteotome 600 as in FIG. 21-22B
was configured with a helical spring that had a collapsed length of
1.8 mm and an extended length of 7.5 mm. In this embodiment, the
surface area of the spring electrode 625 when extended was 64.24
mm.sup.2 and the total length of the electrodes edges was 171.52 mm
(four edges at 42.88 mm per edge).
In a comparison test, a first osteotome without a helical electrode
was compared against a second osteotome 600 with a helical
electrode as in FIG. 22B. These devices were evaluated at different
power levels and different energy delivery intervals to determine
volume of ablation. The working ends of the devices had similar
dimensions excepting for the helical spring electrode. Referring to
FIG. 22C, RF energy was delivered at a low power setting of 5
Watts. It can be seen in FIG. 22C that at a treatment interval of
120 seconds and 5 W, the volume of ablation was about 3 times
faster with the helical electrode compared to the working end
without the helical electrode (1.29 cc vs. 0.44 cc).
Another comparison test of the same first osteotome 500 (FIG. 18B)
and second osteotome 600 with a helical electrode (FIG. 22B) were
evaluated at higher 15 Watt power level. As can be seen in FIG.
22D, RF energy at a treatment interval of 25 seconds and 15 W, the
volume of ablation was again was about 3 times faster with the
helical electrode compared to the working end without the helical
electrode (1.00 cc vs. 0.37 cc). Referring to FIG. 22D, the device
without the helical electrode impeded out before 60 seconds passed,
so that data was not provided. The testing shows that the helical
electrode is well suited for any type of tissue or tumor ablation,
with a 60 second ablation resulting in 1.63 cc of ablated
tissue.
FIG. 23 schematically illustrates the osteotome 600 in use in a
vertebral body, wherein the RF current between the electrodes 625
and 640 ablate a tissue volume indicated at 640.
FIG. 24 is an enlarged sectional view of a working end 710 of
ablation osteotome similar to that of FIGS. 21-22B. In this
embodiment, shaft or introducer sleeve assembly 712 has an outside
diameter of 4.5 mm or less, or 4.0 mm or less. In one embodiment,
the diameter of introducer 712 is 3.5 mm and comprises outer sleeve
715a, intermediate sleeve 715b and inner sleeve 715c all of which
are slotted to permit articulation of a portion of the working end
as can be seen in phantom view in FIG. 24A.
In FIG. 24, the extendable element or sleeve 720 is shown in an
extended configuration which extends helical spring element 725 as
described above. In this embodiment, the sleeve 720 and helical
spring element 725 together with sharp tip 730 comprises a first
polarity electrode coupled to an RF source 530A and controller 530B
as described previously. An insulator 732 separates the helical
spring 725 electrode from the distal portion 734 of the sleeve
which comprises opposing polarity electrode 740. It can be seen
that extendable sleeve 720 has a distal portion that is slotted to
permit bending as the working end is articulated. The RF electrodes
can function as described above (see FIG. 20) to ablate tissue.
In one aspect of the invention, the electrode surface portion of
the extendable assembly 735 (sleeve 720 and helical element 725) is
moveable from a non-extended position to an extended position
during which the electrode surface area varies less than 10%
between said non-extended and extended positions. In another
embodiment, the electrode surface area varies less than 5% between
said non-extended and extended positions. This aspect of the
invention allows for similar ablation volumes per unit time no
matter the dimension of the extendable assembly 735 since the
surface are of the helical element 725 accounts for nearly all of
the electrode surface area. The extendable element can have an
electrode surface area of at least 40 mm.sup.2, at least 50
mm.sup.2, or at least 60 mm.sup.2.
FIG. 24 further illustrates another aspect of the invention which
includes at least one temperature sensor, referred to as a
temperature detecting element, in the working end for controlling
or terminating RF energy delivery when tissue adjacent the
temperature reaches a predetermined level.
In one variation, as shown in FIG. 24, a temperature detecting
element 745 can be disposed between first and second dielectric
sleeves 746 and 748 that insulate the introducer sleeve assembly
712 from the extendable sleeve 720. In an embodiment, the RF energy
can be activated to ablate tissue until the boundary of ablated
tissue adjacent the temperature detecting element 745 reached a
predetermined temperature and the temperature detecting element
signal can then be coupled to the controller to terminate RF energy
delivery. In on embodiment, the temperature detecting element 745
can be disposed between first and second layers of a thin wall
dielectric material, 746 and 748, such as PEEK that is used to
insulate the opposing polarity electrodes from each other. In FIG.
24, the temperature detecting element 745 can be positioned
dimension AA from the distal end of the introducer sleeve assembly
712 which can range from 5 mm to 15 mm. FIG. 24 depicts a second
temperature detecting element 750 that can be positioned dimension
BB from the first temperature detecting element 745 which can be a
distance ranging from 5 mm to 15 mm.
As shown FIG. 24, a temperature detecting element 745 can be
disposed on an outer radius of an articulated distal portion of the
working end. In another embodiment, the temperature detecting
element(s) can be disposed on an inner radius of the articulated
distal portion of the working end.
In FIG. 25, it can be seen that the helical element 725 has a
distal end coupled, for example by weld 752, to the distal tip
element 730 of the extendable assembly 735. FIG. 25 further shows
that helical element 725 has a proximal end coupled to a safety
wire 760 that extends proximally and is bonded to the introducer
assembly, for example being secured with adhesives or other means
between the first and second layers of dielectric material, 746 and
748.
In one embodiment shown in FIG. 25, a conductive fluid source 765
communicates with a lumen 770 extending through the extendable
sleeve 720 to provide saline infusion through ports 772 into the
region of tissue targeted for treatment.
In general, a method corresponding to the invention comprises
introducing an elongated introducer sleeve comprising return
electrode into targeted tissue, articulating a distal region of the
introducer sleeve and extending an extendable member from the
introducer sleeve, wherein the extendable member comprises an
active or first polarity electrode having an electrode surface area
that varies less than 10% between non-extended and extended
positions, and activating an RF source, such that when activated,
current flows between the extendable member and the introducer
sleeve to apply energy to the targeted tissue. The method includes
terminating activation of the RF source when a temperature sensor
spaced apart from the first polarity electrode reaches a
predetermined temperature. The temperature sensor can be spaced
apart from the first polarity electrode by at least 5 min, 10 mm or
15 mm. The method can target tissue in or near a bone such as a
vertebra or long bone. The targeted tissue can be a tumor.
Another method of the invention comprises treating a tumor in or
near bone which includes providing an elongated shaft with an
articulating working end carrying first and second polarity
electrodes, utilizing articulation of the working end to navigate
the working end to a position in or near a bone tumor, activating
an RF source, such that when activated, current flows between the
first and second polarity electrodes to ablate the tumor; and
terminating activation of the RF source when a temperature sensor
spaced apart from the second polarity electrode reaches a
predetermined temperature, in this method, the temperature sensor
spacing from an active electrode is configured to provide a
predetermined tissue ablation volume. As shown in FIG. 24, the
working end can carry a plurality of axially spaced apart
temperature sensors, and each sensor can be used to indicate a
particular dimension of ablated tissue as each sensor reaches a
predetermined temperature based on the expanding volume of ablated
tissue.
In another embodiment, the medial and proximal regions of the outer
sleeve can be covered with a thin-wall insulative material to
provide an distal electrode surface having a predetermined surface
area that matches the surface area of the helical element 725. The
sleeve 720 at the interior of the helical element also can be
covered with a thin-wall dielectric material. In use, the device
then would operate in a truly bi-polar manner since the opposing
polarity electrodes would have an equal surface area no matter the
length of extension of the extendable assembly 735. In general, a
device corresponding to the invention would comprise an elongate
introducer having a distal end, wherein a surface portion of the
introducer comprises an electrode, an extendable member including a
helical element comprising an second electrode moveable from a
non-extended position to an extended position from the introducer
wherein the electrode surface area of the first electrode and the
second electrode match no matter the non-extended or extended
position of the second electrode.
In another variation of the invention under the present disclosure,
the devices, systems and methods described herein can include the
use of one or more temperature sensors (also called temperature
detecting elements) to monitor, control, and/or otherwise provide a
physician with the information needed to ensure a desired
treatment.
The temperature sensor/temperature detecting element can comprise
any element that can measure temperature of the adjacent tissue or
measure temperature of the device immediately adjacent to tissue
provide this information to a controller or other portion of the
system as described herein. In most variations of the device, the
temperature detecting element is used to assess temperature of the
tissue before, during, or after application of energy. Examples of
temperature detecting elements include thermocouples, resistance
temperature detectors (RTDs), optical temperature measurement
sensors, pyrometers. In addition, the present disclosure can
include any type of temperature measurement device capable of
determining a temperature of tissue or even parts of the device
that would otherwise indicate a relative temperature of the
tissue.
FIG. 26A illustrates a device similar to that shown in FIG. 24
where a temperature detecting element 745 is disposed between first
and second dielectric sleeves 746 and 748 that insulate the
introducer sleeve assembly 712 from the extendable sleeve 720. As
shown the temperature detecting element 745 can be disposed on an
outer radius of an articulated distal portion of the working end.
In addition, FIG. 26A shows a second temperature detecting element
750 positioned proximally from the first temperature detecting
element 745 where spacing of such temperature detecting elements
allows for control and/or monitoring a region of heated tissue as
described below. However, variations of the devices allow for any
number of temperature detecting elements to be used in any number
of positions.
For example, FIG. 26B illustrates two temperature detecting element
245, 250 positioned on an exterior sleeve 715A of the device. In an
additional variation, the temperature detecting elements can be
positioned in between the slots of the exterior sleeve 715A.
FIG. 26C shows another variation of a device having a plurality of
temperature detecting elements 745, 750, 754, 756, 758 spaced along
the shaft. Clearly, the temperature detecting elements could be
located on an interior of the device, similar to that shown in FIG.
24A. Alternatively, as shown in FIG. 26D, temperature detecting
elements can be included both on an interior and exterior of the
device. FIG. 26E illustrates temperature detecting elements 745,
750, 754 located on both sides of the device. Alternatively, the
temperature detecting element can comprise a ring type element that
measures temperature adjacent to a full or partial circumference of
the device. As noted herein, the temperature detecting elements can
be evenly spaced along the shaft. Alternatively, the spacing of the
elements can vary depending upon the intended application of the
device. In addition, in most variations of the devices described
herein, the temperature detecting elements are located proximally
to the heating element of the device. However, additional
variations include temperature detecting elements positioned distal
to or adjacent to the heating element. The components of the
various temperature detecting elements, such as wires, fibers, etc.
are not illustrated for purposes of clarity. Furthermore, one or
more temperature detecting elements can be positioned on sleeves
that move axially relative to the energy transfer portion.
FIGS. 27A to 27C illustrate a concept of using temperature sensing
element to guide a treatment where the temperature sensing elements
are placed away from the energy transfer unit. FIG. 27A shows an
example of a treatment device 800 having energy transfer portion
802 at a distal portion of a shaft 804. As discussed above, one
effective variation of a device includes the use of RF energy
configuration, either monopolar or bi-polar, that serves as the
energy transfer portion. However, any number of energy transfer
modes can be employed in the methods, systems and devices described
herein where such modalities produced heated tissue. Such
modalities can include, but are not limited to, resistive heating,
radiant heating, coherent light, microwave, and chemical. In yet
another variation, the devices can use radioactive energy
modalities as well. Alternatively, variations of devices employing
temperature based detection can employ cryosurgical energy
configurations that rely upon the application of extreme cold treat
tissue. Clearly, in such cases the methods, devices, and systems
would monitor regions of cooled tissue rather than heated
tissue.
Turning back to FIG. 27A, the treatment device 800 includes at
least a first temperature detecting element 806 located axially
relative to an energy transfer element 802. In some variations, the
energy transfer element 806 is located proximally along an axis of
the shaft from thee energy transfer unit 802. However, as described
above, variations of the devices include placement of the
temperature detecting elements as needed. FIG. 27A also shows a
second temperature detecting element 808 located proximally to the
first temperature, detecting element 806. Again, the methods and
procedures described herein can employ any number of temperature
detecting elements.
The devices and methods also optionally include conveying
temperature information on a controller 830. Variations of the
controller 830 allow for display or conveyance of temperature
information specific to each temperature detecting element. For
example, in the variation shown in FIG. 27A, the first temperature
detecting element can be coupled to display 832 while the second
temperature detecting element 808 can be coupled to display 834.
The controller can also optionally allow a physician to set
temperature limits based on readings from each temperature sensing
element. In such a case, if a measured temperature at a respective
temperature sensing element exceeds the temperature limit, the
system can end delivery of the energy or provide any other auditory
or visual alert. The control unit 830 can be separate from a power
supply of can be integrated into the power supply. Additional
variations also include a control unit that can be integrated into
a handle or other portion of the device 800.
In a first variation, a physician can position the distal end of
the shaft 804 containing the energy transfer element 802 within a
tumor 12. Clearly, the methods and procedures are not limited to
treatment of a tumor. Instead, the device can be positioned in any
target region that a physician seeks to treat. Once the device 800
and energy transfer element 802 are properly positioned, the
physician can begin to apply energy to the energy transfer portion
to cause an effect as shown by arrows 14) in tissue that produces a
region of affected tissue, e.g., a temperature of the tissue
increases or decreases (as described above based on the energy
modality used). For convenience, the method shall be discussed with
respect to an area of heated tissue. Clearly, alternate variations
of the device involve regions of cooled tissue.
FIG. 27B illustrates continued application of energy, which results
in expansion of the region of heated tissue 16. The continued
application of energy can occur intermittently or continuously. As
the physician operates the device 800, the temperature detecting
elements 806, 808 can monitor temperature of adjacent tissue. FIG.
27B depicts the region of heated tissue 16 as not having yet
reached the first or second temperature sensing element 806, 808.
The temperature measurements can occur intermittently,
continuously, during application of energy, or in between
intermittent applications of energy. Likewise, the temperature
information 832, 834 can optionally be relayed to the controller
830.
FIG. 27C shows the heated region of tissue 16 expanded sufficiently
such that it encompasses the desired region of tissue 12 or tumor.
FIG. 27 also depicts the heated region of tissue 16 as being easily
visually identified. However, during an actual treatment, the
physician simply cannot observe the actual perimeter of the zone of
heated tissue 16. Instead, the temperature detecting elements 806,
808 will be able to detect the heated region of tissue 16 as the
temperature of the tissue adjacent to the temperature detecting
elements 806, 808 rises.
The temperature measured by the temperature detecting elements 806,
808 can also provide the physician with the ability to monitor the
progression of the region of heated tissue 16. For instance, the
volume, length, area, or other characteristic of the region of
heated tissue can be approximated by obtaining a temperature that
is associated with the perimeter of the region. Analytic
correlation of this associated temperature to the physical
characteristic of the heated tissue can be determined from bench
testing, animal testing, cadaver testing, and/or computer analysis.
Such analytic correlation allows the volume of an area of heated
tissue to be approximated based on the temperature of the outer
perimeter of that region. In the illustrated example of FIG. 27C,
there exists a pre-determined temperature associated with an area
of heated tissue having known dimension. Once the measured
temperature at temperature detecting element 808 reaches this
associated temperature, the physician can stop the treatment.
Alternatively, or in addition, the system or controller 830 can
include safety algorithms to automatically warn the physician to
cease treatment or even to perform a safety shutoff of the system
if a given temperature is reached or if the temperature remains
constant while power is applied to the electrode.
In additional variations, the monitoring of the size or profile of
the region of heated tissue can be used to control the application
of applied energy. For example, as the measured temperature
approaches the associated temperature, the controller can reduce
power to prevent any lags in measurement from overshooting the
target treatment zone.
The variation described above in FIGS. 27A to 27C can also be used
to position the device 800 relative to a desired target region 12.
For example, the temperature detecting elements 806, 808, can be
radiopaque (or can have radiopaque markers) so that a physician can
place the appropriate temperature detecting element in a target
area or at a perimeter of the target area. In the example shown in
FIG. 27A, a physician could position the second temperature
detecting element 808 just outside of a tumor or as otherwise
desired. Once the measured temperature reaches the associated
temperature the physician can stop application of energy and
reposition the device as needed or stop treatment.
E.g. A physician may choose to use 50C or 55C as a target
temperature for a specific temperature detecting element based on
pre-planning. Once that temperature reaches the desired level; e.g.
50C or 55C then the physician may stop delivering any further
energy to the tissue by turning off energy delivery. In another
embodiment, controller will have an algorithm where a physician
inputs the desired temperature for a specific temperature detecting
element and controller will apply energy. Energy delivery will stop
once the desired temperature is achieved. Further enhancement to
the controller may also allow physician with an ability to set
desired amount of time associated with each target temperature
where controller will maintain energy level sufficient to control
the temperature for desired amount of time and then turn of the
energy delivery.
FIG. 27A also depicts a variation of the device as having visible
markers 814, 816, and 818 located on a shaft. The markers can be
used to assist the physician in positioning of the energy transfer
elements and/or temperature detecting elements. For example, in the
illustrated variation, the device can be used with an introducer
cannula of a known size so that marker 814 informs the physician
that the distal tip or energy transfer element is positioned at the
opening of the cannula. Likewise, markers 816 and 818 can inform
the physician that energy transfer elements 806 and 808 are
respectively located at the opening of the cannula.
Although particular embodiments of the present invention have been
described above in detail, it will be understood that this
description is merely for purposes of illustration and the above
description of the invention is not exhaustive. Specific features
of the invention are shown in some drawings and not in others, and
this is for convenience only and any feature may be combined with
another in accordance with the invention. A number of variations
and alternatives will be apparent to one having ordinary skills in
the art. Such alternatives and variations are intended to be
included within the scope of the claims. Particular features that
are presented in dependent claims can be combined and fall within
the scope of the invention. The invention also encompasses
embodiments as if dependent claims were alternatively written in a
multiple dependent claim format with reference to other independent
claims.
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